Nonwoven fabrics produced by the meltblowing and spunbonding process have found great utility in many diverse applications from car and boat covers to incontinence products. Different attributes or properties of the fabric are required depending on the application. A car cover, for example, must have great tensile strength and resistance to ultraviolet radiation, while a feminine hygiene product must exhibit great absorbency and softness. Developing just the right combination of properties for the application is a complex task requiring the focused attention of many highly qualified individuals.
The bonding pattern used in either bonding the fibers of the nonwoven fabric to itself or in bonding the nonwoven fabric to other material layers can cause great changes in the fabric properties. Bonding patterns with large bond areas, for example, tend to make a strongly bonded but rough feeling fabric. Those with small bond areas tend to make soft feeling but very weak fabric.
Various attempts have been made at overcoming the disadvantage seemingly inherent in higher bond areas, i.e. decreased softness. One such attempt is taught in U.S. Pat. No. 5,620,779 to Levy and Mcormack and is a nonwoven fabric with a bond pattern having a certain required spacing ratio which is then stretched to produce ribs.
A number of treatments have also been developed to soften nonwoven fabrics such as multiple washings and chemical treatments.
There remains a need, however, for an unribbed fabric without chemical treatments having good bonding strength (i.e. tensile strength and abrasion resistance) yet also having good fabric softness without excessive bonding area.
Accordingly, it is an object of this invention to provide a nonwoven fabric with a bonding area comparable to fabrics bonded with known patterns yet having greater softness and comparable or better tensile strength and abrasion resistance.